The present invention relates to the quality control of the sealed sterile packaging process. Various micro objects (e.g., human hair, dust, injection molding debris, etc.) can become embedded between sealing surfaces, which can compromise the sealing of sterile surgical instruments in a sterile package. It is desirable to automatically identify defective package sealing products since the use of human operators to perform this task is costly and unreliable.
While the largest defects (discontinuities or voids) can be found using a conventional optical inspection system such as that described in U.S. Pat. No. 6,097,427, issued Aug. 1, 2000, by taking an video image of sealing areas, it is difficult to recognize micro defects or embedded objects with characteristic dimensions less than a hundred microns on large inspection areas during manufacturing process. Attempts to increase magnification of the optical system to increase object resolution will cause decreasing the camera field area resulting in impractical images, long processing time, or complex visual system setups.
U.S. Pat. No. 5,155,790 issued Oct. 13, 1992, describes an electronic scanner or printer with fiber optic bundles. This system uses unique optical fiber bundles for the optical subassembly to transfer images. The fiber bundle is organized so that first face (scanner) has a linear geometry and the second face has area geometry. In the scanner configuration the fiber optic linear bundle transmits image pixels to the face, which is then mechanically scanned into the video system and memory for future image processing. The linear face comprises nominally 5100 square fibers that covers up to 8.5 inches of a document with the fiber core diameter being about eight microns. Such a scanner, however, cannot be applied to the scan packaging area for several reasons: the scanning area is not flat and its scanning speed is too slow for real time defects detection.
What is needed in the packaging art are improved methods and systems for detecting defects and contamination (e.g., embedded objects) in sealed, sterilized packaging before it is shipped from packaging operations to customers.